Relationships of Dissolved Oxygen with Chlorophyll-a and Phytoplankton Composition in Tilapia Ponds

Abstract

This study investigated the relationships among the parameters of dissolved oxygen, chlorophyll-a and phytoplankton composition in tilapia ponds. Each pond (a total of 18 ponds) was sampled once in the dry, winter season between January and March and again early in the rainy season between May and June. The data were analyzed by examining correlations among parameters as affected by season, altitude and culture system. Observations were made at sites located in 5 selected provinces of northern Thailand: Chiangrai, Chiangmai, Phayao, Lampang and Nakornsawan. Mean elevation of these areas range from 25 to 582 meters above sea level (masl) and were categorized into low (<400 masl) and high (>400 masl) elevation sites. Ponds were 0.8-2.0 m deep, 0.16-0.64 ha in area and could be further categorized into high and low input systems.Mean air temperature in winter ranged between 16.5˚C-35.8˚C while mean water temperature ranged between 25.5˚C-27.1˚C. In rainy season, air temperature ranged between 22.0˚C-37.3˚C and water temperature ranged between 29.4˚C-31.8˚C. The amount of chlorophyll-a in both seasons were comparable (p > 0.05), but chlorophyll-a in high input system was significantly higher (p < 0.05) than in low input ponds. Only weak correlation was found between chlorophyll-a, DO max and DO min. Multifactor-ANOVA was used to analyze the difference of total bacteria and filamentous cyanobacteria in ponds based upon elevation, culture systems and season. Result shows that there is a significant interaction observed between elevation, culture system and season (p < 0.05). Species diversity and composition of phytoplankton in fish ponds in 2 seasons revealed the presence of 90 genera of phytoplankton under all 7 divisions. Divisions Chlorophyta and Cyanophyta had the most number of genera identified in both seasons with Pediastrum spp., and Scendesmus spp., and Anabaena spp. as dominant genera/genus, respectively.

Evaluation of Water Variables in No-Take Zone of Ustica Marine Protected Area (Southern Tyrrhenian Sea)

“…Oxygen super saturation (values > 120%), can indicate elevated phytoplankton photosynthesis and this is confirmed by the abundant presence of PK (data not showed) observed during this seasons (28,29). DO shows a significant negative correlation with pH (P<0.001), that should be in part confirmed by Frieder et al (2012) (30), in case of high values of DO, and also with Chl-a (P<0.001), as also reported by Kunlasak et al (2013) (31). Concentrations of salt nutrients and Chl-a are summarized in Tables 1A and B and reported as graph in Figure 4, with median, 25% and 75% percentile, maximum and minimum highlighted.…”

Influence of alum on cyanobacterial blooms and water quality of earthen fish ponds

“…The recorded decrease of oxygen concentration during treatment with alum compared with control is attributed to the decrease in phytoplankton growth. As dissolved oxygen saturation point is 8.5 mg L −1 at 25°C, the increase in dissolved oxygen recorded in Table 3 confirms that the dissolved oxygen was affected not only by algal photosynthesis but also by aquatic respiration, oxidative decomposition of settled organic compounds such as nutrients, fish, and animal wastes (Kunlasak et al 2013). Koohestanian et al (2008) stated that 85-98 % reduction of water turbidity can be achieved using the optimum coagulant dosage (8 mg L −1 ferric chloride and 10 mg L −1 alum) in the optimum pH range (9.2 for ferric chloride and 8.5 for alum) which is in agreement to the present results.…”

Applications of microalga Chlorella vulgaris in aquaculture

“…Chlorophyll-a concentration above 0.2 mg m À3 is good enough to increase planktonic activity which ultimately assists in improving fish activity (Zainuddin et al 2004). Study on levels of chlorophyll-a in tilapia pond revealed that, an increase in plankton high in chlorophyll-a yields a higher concentration of dissolved oxygen (Kunlasak et al 2013). Chlorin and phytol are metabolites of chlorophyll and are reported to have antioxidant and anticarcinogenic effect in various kinds of marine fish, with phytol as an essential nutrient that regulates cellular metabolism (Ma & Dolphin 1999).…”